1. Field of the Invention
The invention relates generally to shape charges and the jets created by them, and more particularly to a shape charge holder that can effect the simultaneous detonation of three or more shape charges, therein creating jets that converge at a point within a target.
2. Background
The NAVORD REPORT 1248, a MANUAL FOR SHAPED-CHARGE DESIGN By Robert A. Brimner, intended for the practical designer of shaped charges, is a scientific treatise on the art of making shape charges. It contains multiple passages on how the effectiveness of charges can be negatively impacted by a number of factors. The factors include casting imperfections, such as bubbles, and the location of the bubbles. Bubbles near the base of the liner are much more troublesome than if they occur close to or at the apex. Near the liner bubbles reduce penetration, while near the apex little harm is done.
The report teaches that cone inclination and charge axis may be inclined only 0.5 degrees with respect to each other without causing serious impairment of the jet formation and subsequent penetration.
A cone may show an ellipticity of 1 percent of the cone diameter without significant effect on the performance. A difference of 1.7 percent results in a decrease of more than 10 percent in penetration.
A triangularly deformed cone showing a difference of as much as 1 percent of the base diameter gives a penetration 10 percent below the normal. A difference of 0.5 percent may be tolerated without significant harmful effect.
An off-center placement of the detonator displacement (10 percent of the charge diameter) will cause scattering of the jet and a decrease in the depth of penetration unless the charge is very long.
Wires, rods, and other solid inert materials in the cavity of the cone adversely affect penetration by interfering with the jet formation.